Trả lời :
( X + 1 ) + ( X + 2 ) + ( X + 3 ) + ( X + 4 ) + ( X + 5 ) = 90
=> ( X + X + X + X + X ) + ( 1 + 2 + 3 + 4 + 5 ) = 90
=> ( X x 5 ) + 15 = 90
=> X x 5 = 90 - 15
=> X x 5 = 75
=> X = 75 : 5
=> X = 15.
Vậy X = 15.
Học tốt nha~
X + (1+2+3+4+5) = 90
X+ 15 = 90
X = 90-15
X = 75
Ta có ( X+1) + (X+2) + ( X+3) + ( X+4) + ( X+5)=90
<=> X+1+X+2+X+3+X+4+X+5 = 90
<=> ( X+X+X+X+X) + ( 1+2+3+4+5) = 90
<=> 5X + 15 =90
<=> 5X= 90 -15= 75
<=> X = 75:5
<=> X= 15
Vậy X =15
nhớ tích cho mk nha :>
(X+X+X+X+X) + (1+ 2+3+4+5)
5x + 15 = 90
5x = 75
x = 75 : 5
x = 15
(X+1)+(X+2)+(X+3)+(X+3)+(X+4)+(X+5)=90
X+(1+2+3+4+5) =90
X+15 =90
X =90-15
X =75
# CHÚC BẠN HỌC TỐT #
\(\left(x+1\right)+\left(x+2\right)+\left(x+3\right)+\left(x+4\right)+\left(x+5\right)=\)\(90\)
\(\left(x+x+x+x+x\right)+\left(1+2+3+4+5\right)\)\(=90\)
\(x.5+15=90\)
\(x.5=90-15\)
\(x.5=75\)
\(x=75\div5\).
\(x=15\)
Vậy \(x=15\)
Hok tốt !